Using electrical measurements to determine the self-field AC losses of cable models

The DC current distribution and self-field AC losses of three HTS cable mod els have been measured electrically. Each cable consisted of one or two lay ers of spirally wound Bi-2223 tape. Non-uniform distributions of the curren t were found, due to variations in terminal resistances and tape degradatio n during winding. This meant that caution was required in the placing of le ads for measuring the in-phase voltage and in the resultant calculation of AC loss. Three different configurations for the voltage leads were employed and the disadvantages of each are discussed. The calculated AC losses are compared to theoretical models and interpreted, considering the influence o f the non-uniform current distribution on the measurements. (C) 1998 Elsevi er Science B.V. All rights reserved.